It doesn't do it on any other size, but it will do it on a brand new map with the exact same details (as below).- You can build over it.- You can see into it- It shows no matter the environmental conditions

Yeah @RedKetchup , it looks like it's a water texture bug of some form. & @Nilla yeah, I moved on pretty quickly from this map. Saved it cos it was interesting, but otherwise happily building on a new map

Please ... please, please, please make that into an Easter Egg, or Christmas Basket treat ... that is far, far too AmazeBalls to miss out on .... hahaha, that made my day, and I didn't need glasses for it